In order to maximize energy production and avoid unscheduled stops in large plants producing electricity there are different techniques and systems for assessing the insulation state of their generator. These technique and/or systems use special equipment so that when facing an incipient failure in the generator electrical insulation an appropriate corrective maintenance can be programmed.
As in other industrial sectors, in the wind industry would be advisable to monitor the insulation state of generators to avoid the negative consequences that occur in case of failure. In a wind turbine a failure in the generator insulation makes necessary a replacement thereof due to the difficulty for carrying out its on-site repair. Furthermore, in the case of wind power, wind turbines are often installed in places far from an industrial environment and, thus, a generator replacement involves a long repair time and a considerable loss of energy produced.
However the techniques used for assessing the generator insulation state in other industrial sector such as, for example, the electrical generators of conventional thermal or hydroelectric plants are not applicable to wind turbines. The reason is that conventional plants are equipped with a generator of high power, for example 50MVA and above, while a wind farm of the same power can be formed by several wind turbines with generators having a power lesser than 10MVA. Therefore, to detect generator insulation faults in a wind farm, a fault detection system should be installed in each generator increasing significantly the system cost.
In other words, those methods that require the use of specific equipment to monitor the status of each generator in a planned manner throughout its lifetime are not profitable in the wind industry.
It would be, therefore, desirable for the wind industry methods and systems specifically designed to detect insulation failures of wind turbine generators not needing to incorporate additional elements for that task as well as to their integration into existing wind turbines so that their cost is not increased.
The present invention is directed to the attention of these demands.